Isotope tracing of submarine groundwater discharge offshore Ubatuba, Brazil: results of the IAEA–UNESCO SGD project

Results of groundwater and seawater analyses for radioactive (³H, ²²²Rn, ²²³Ra, ²²⁴Ra, ²²⁶Ra, and ²²⁸Ra) and stable (D and ¹⁸O) isotopes are presented together with in situ spatial mapping and time series ²²²Rn measurements in seawater, direct seepage measurements using manual and automated seepage meters, pore water investigations using different tracers and piezometric techniques, and geoelectric surveys probing the coast. This study represents first time that such a new complex arsenal of radioactive and non-radioactive tracer techniques and geophysical methods have been used for simultaneous submarine groundwater discharge (SGD) investigations. Large fluctuations of SGD fluxes were observed at sites situated only a few meters apart (from 0 cm d⁻¹ to 360 cm d⁻¹; the unit represents cm³/cm²/day), as well as during a few hours (from 0 cm d⁻¹ to 110 cm d⁻¹), strongly depending on the tidal fluctuations. The average SGD flux estimated from continuous ²²²Rn measurements is 17 ± 10 cm d⁻¹. Integrated coastal SGD flux estimated for the Ubatuba coast using radium isotopes is about 7 × 10³ m³ d⁻¹ per km of the coast. The isotopic composition (δD and δ¹⁸O) of submarine waters was characterised by significant variability and heavy isotope enrichment, indicating that the contribution of groundwater in submarine waters varied from a small percentage to 20%. However, this contribution with increasing offshore distance became negligible. Automated seepage meters and time series measurements of ²²²Rn activity concentration showed a negative correlation between the SGD rates and tidal stage. This is likely caused by sea level changes as tidal effects induce variations of hydraulic gradients. The geoelectric probing and piezometric measurements contributed to better understanding of the spatial distribution of different water masses present along the coast. The radium isotope data showed scattered distributions with offshore distance, which imply that seawater in a complex coast with many small bays and islands was influenced by local currents and groundwater/seawater mixing. This has also been confirmed by a relatively short residence time of 1–2 weeks for water within 25 km offshore, as obtained by short-lived radium isotopes. The irregular distribution of SGD seen at Ubatuba is a characteristic of fractured rock aquifers, fed by coastal groundwater and recirculated seawater with small admixtures of groundwater, which is of potential environmental concern and has implications on the management of freshwater resources in the region.     

Horizontal mergers in the iron ore industry—An application of PCAIDS

The purpose of this paper is to estimate and analyse the price effects of the iron ore mergers between Rio Tinto and North Ltd in 2000, and CVRD and Caemi in 2001. The analyses are conducted using a merger simulation model that, based on the pre-merger situation, estimates the post-merger outcome. This paper applies the so-called proportionality-calibrated almost ideal demand system (PCAIDS) model, which assumes that the product is differentiated and that the strategic variable is price. The results from the merger simulations show that in the case of the merger between Rio Tinto and North Ltd, the merged firm has a combined market share of almost 20%. However, the estimated market weighted average price effect is only 2.6%. Regarding the merger between CVRD and Caemi, the merged firm's market share is about 29%, and the estimated market weighted average price effect is 4.6%. When removing Caemi's Canadian asset, which was the Commission decision in order to allow the merger, the market price effect decreases to 3.1%. Overall the results in this study support the Commission's decisions regarding both merger cases, and shows that merger simulations of price effects can be valuable tools in merger assessments.     

漓江流域δD和δ18O对蒸发的指示作用

以漓江流域为例查明不同水体之间氢氧稳定同位素组成特征,并探讨氢氧稳定同位素对漓江流域的蒸发过程指示作用.结果表明：流域内不同水体之间,氢氧稳定同位素表现出不同的组成特征,地表水和地下水,在丰水期δD值和δ¹⁸O值要比枯水期更容易富集,地下水的δD值和δ¹⁸O值分布范围较地表水小;随着水温的升高,δ¹⁸O的变化趋势比d-excess明显.从漓江上游到下游高程逐渐下降,河水线的斜率和截距也在逐渐减小,其中漓江下游河水线的斜率和截距要低于当地大气降水线,表明下游受到蒸发作用较强烈;地下河水线、地表河水线在一定程度上偏离当地大气降水线,但偏离程度较小,表明三者之间有很好的水力联系.受温度和湿度的共同影响,漓江干流丰水期河水的蒸发量占最初水体总量的0.7%~9.1%,枯水期河水的蒸发量占最初水体总量的2.6%~9.7%,丰水期的蒸发比例低于枯水期,从上游到下游蒸发比例在逐渐上升.研究区蒸发量估算值为959.40mm,与多年实测值少43.11mm,相对误差4.70%.氢氧稳定同位素对研究区降水、地表水、地下水之间的转换规律具有重要的实际意义,在今后的漓江流域水文研究中有着更加广阔的空间.     

新疆D矿田金矿资源定量评价

本文在建立D矿田找矿信息层次模型基础上,确定矿田统计单元划分和地质变量提取的赋值原则,将该矿田划分出466个统计单元,提取25个地质变量并进行二态赋值,而后应用数量化理论Ⅲ。特征分析法及勃尔法等方法,建立了矿田金矿资源定量评价模型,定位预测了45个勘探靶区。     

Growth responses of Picea mongolica seedlings to defoliation rate

Picea mongolica W. D. Xu. is an endemic species in China. The spruce forest is only found in semi-arid habitat in Inner Mongolia Autonomous Region of China. Based on the simulative defoliation experiment, it was proved that Picea mongolica seedlings had the compensatory and overcompensatory effects under the certain defoliation rate. The results of variance analysis on growth indexes showed that in PM I (natural regeneration seedlings under Picea mongolica forest), the differences of H1 (height in June 23 ) and H2 (height in September 3) were extremely significant, and the difference of D(diameter at the breast height) were not significant. In PM Ⅱ (artificial regeneration seedlings under Betula platyphylla Suk. forest), the difference of H1 was significant, the difference of H2 was not significant, and the difference of D was extremely significant. The regression equations were established and the compensatory and overcompensatory points were obtained. In PM I, the compensatory points of H1, H2, and D were 0.7628, 0.7436, 0.5725, and the overcompensatory points were 0.6056, 0.5802 and 0.2909 respectively. In PM Ⅱ, the compensatory points of H1, H2, and D are 0.5012, 0.3421, 0.2488, and the overcompensatory points are 0.4137, 0.2633 and 0.0747 respectively. These results suggested that the induction of compensatory growth mechanisms in spruce seedlings required a threshold level of defoliation, and the insects in Picea mongolica forest could be controlled in a certain de clree.     

金堆城超大型钼矿床水-岩δD-δ~(18)O同位素交换体系理论模型及成矿流体来源

基于水-岩δD-δ18O同位素交换体系理论模型的建立和计算，对金堆城超大型斑岩钼矿四个不同成矿期中成矿流体的演化和来源进行了研究，发现在成矿前期和早期，成矿流体为岩浆水与围岩在较低水／岩比值（0．1W／R＞0．001）和中、高温（t=250～500℃）条件下反应后的残余流体，而主成矿期和成矿晚期的成矿流作为大气降水在相对较高水／岩比值（0．5＞W／R0．1）和中、低温（t＝150～310℃）条件下与围岩反应后的残留流体。大气降水在金堆城钼矿成矿过程中起了重要作用。在主成矿期水／岩比值达到最高。     

Dobbins-Camp水质模型的修正

对多宾斯 坎普 (Dobbins Camp)水质模型进行了修正 ;并分别运用传统多宾斯 坎普模型和修正模型 ,对某河段实测资料进行BOD、D(氧亏 )计算 ,比较两者之间的异同 ,及分析溶解氧对有机物降解的影响     

无缝钢管局部径向模具塑性成形过程的三维有限元数值模拟

采用大变形弹塑性有限元理论,用DYNA3D(研究版)有限元软件,对无缝钢管局部径向模具塑性成形过程中当凸模的凹槽尺寸与凸模的圆弧半径发生变化时进行了数值模拟研究,得出了对成形钢管表面质量控制具有重要参考价值的结论,解决了成形钢管表面的压痕问题。     

Estimation of building-related construction and demolition waste in Shanghai

One methodology is proposed to estimate the quantification and composition of building-related construction and demolition (C&D) waste in a fast developing region like Shanghai, PR China. The varieties of structure types and building waste intensities due to the requirement of progressive building design and structure codes in different decades are considered in this regional C&D waste estimation study. It is concluded that approximately 13.71 million tons of C&D waste was generated in 2012 in Shanghai, of which more than 80% of this C&D waste was concrete, bricks and blocks. Analysis from this study can be applied to facilitate C&D waste governors and researchers the duty of formulating precise policies and specifications. As a matter of fact, at least a half of the enormous amount of C&D waste could be recycled if implementing proper recycling technologies and measures. The appropriate managements would be economically and environmentally beneficial to Shanghai where the per capita per year output of C&D waste has been as high as 842 kg in 2010.     

Belowground effects of enhanced tropospheric ozone and drought in a beech/spruce forest (Fagus sylvatica L./Picea abies [L.] Karst)

The effects of experimentally elevated O₃ on soil respiration rates, standing fine-root biomass, fine-root production and δ¹³C signature of newly produced fine roots were investigated in an adult European beech/Norway spruce forest in Germany during two subsequent years with contrasting rainfall patterns. During humid 2002, soil respiration rate was enhanced under elevated O₃ under beech and spruce, and was related to O₃-stimulated fine-root production only in beech. During dry 2003, the stimulating effect of O₃ on soil respiration rate vanished under spruce, which was correlated with decreased fine-root production in spruce under drought, irrespective of the O₃ regime. δ¹³C signature of newly formed fine-roots was consistent with the differing g_s of beech and spruce, and indicated stomatal limitation by O₃ in beech and by drought in spruce. Our study showed that drought can override the stimulating O₃ effects on fine-root dynamics and soil respiration in mature beech and spruce forests.